Question

Two equations are given below: m + 5n = 20 m = n − 4 What is the solution to the set of equations in the form (m, n)? (3, 7) (0, 4) (5, 1) (2, 6)

Answer 1

use subsitution


m+5n=20
m=n-4

sub n-4 for m in other equation

n-4+5n=20
6n-4=20
add 4 both sides
6n=24
divide by 6 both sides
n=4

sub back

m=n-4
m=4-4
m=0

(m,n)
(0,4)

Answer 2

(m,n) = (0,4)

Explanation:

We have

m + 5n = 20 -----------------------eqn 1

m = n - 4 ----------------------------eqn 2

eqn 1 - eqn 2

m + 5n - m = 20 - ( n- 4 )

6n = 24

n = 4

Substituting in eqn 2

m = 4 - 4

m = 0

So the correct set is (0,4)

(m,n) = (0,4)